Abstract: An apparatus for plasma treating a substrate comprises a high voltage source of frequency 3 kHz to 30 kHz connected to at least one needle electrode (11) positioned within a channel (16) inside a dielectric housing (14) having an inlet for process gas and an outlet. The channel (16) has an entry (16a) which forms the said inlet for process gas and an exit (16e) into the dielectric housing arranged so that process gas flows from the inlet through the channel (16) past the electrode (11) to the outlet of the dielectric housing. The apparatus includes means for introducing an atomised surface treatment agent in the dielectric housing, and support means (27, 28) for the substrate (25) adjacent to the outlet of the dielectric housing.

Abstract: A process for plasma treating a substrate comprises applying a radio frequency high voltage to at least one electrode positioned within a dielectric housing having an inlet and an outlet while causing a process gas, usually comprising helium, to flow from the inlet past the electrode to the outlet, thereby generating a non-equilibrium atmospheric pressure plasma. An atomised or gaseous surface treatment agent is incorporated in the non-equilibrium atmospheric pressure plasma. The substrate is positioned adjacent to the plasma outlet so that the surface is in contact with the plasma and is moved relative to the plasma outlet. The velocity of the process gas flowing past the electrode is less than 100 m/s. Process gas is also injected into the dielectric housing at a velocity greater than 100 m/s. The volume ratio of process gas injected at a velocity greater than 100 m/s to process gas flowing past the electrode at less than 100 m/s is from 1:20 to 5:1.

Abstract: A process for plasma treating a substrate comprises applying a radio frequency high voltage to at least one electrode positioned within a dielectric housing having an inlet and an outlet while causing a process gas to flow from the inlet past the electrode to the outlet, thereby generating a non-equilibrium atmospheric pressure plasma. An atomized or gaseous surface treatment agent is incorporated in the non-equilibrium atmospheric pressure plasma. The substrate is positioned adjacent to the plasma outlet so that the surface is in contact with the plasma and is moved relative to the plasma outlet. The flow of process gas and the gap between the plasma outlet and the substrate are controlled so that the process gas has a turbulent flow regime within the dielectric housing.

Abstract: The invention concerns a method for performing chemical reactions between gaseous species in accordance with a selective reaction path, by generating an electric discharge (12) in a starting gas between two energizing electrodes (23, 24) whereto is applied an electric supply voltage, so that the discharge brings about energization of at least one of the gaseous species of said starting gas. The invention is characterised in that it consists in providing the following: the starting gas includes at least a carrier gas and at least a reaction gas; the conditions of electric supply of the electrodes are adapted to enable the generation of metastable species among the species of said carrier gas, so that the ratio, in the inter-electrode space, between the concentration in said metastable species and the concentration in electrons is not less than 1.

Abstract: This method for surface treatment with a plasma at atmospheric pressure comprises the step of introducing a treatment gas into a treatment reactor (16), in which a surface (14) to be treated is placed between two exciting electrodes (22, 24), and applying a supply voltage to the two electrodes so as to cause the appearance of a discharge (12) in the treatment gas. The supply voltage is an AC voltage whose amplitude and frequency are adapted in order to maintain at least some of the components of the treatment gas in the excited state, and/or the presence of electrons, between two successive half-cycles of the supply voltage.

Abstract: Method for creating an electric discharge in an initial gas which is at atmospheric pressure and lies between two exciting electrodes, comprising applying a supply voltage to the two electrodes which is an AC voltage whose amplitude and frequency are adapted in order to maintain (1) at least a portion of the components of the gas in the excited state, and/or (2) the presence of electrons, between two successive half-cycles of the supply voltage.

Abstract: A method and an apparatus for ultrasonically characterizing polymer materials under simulated processing conditions are disclosed. According to the invention, a sample of a polymer is held in confinement between two axially aligned buffer rods having opposed parallel end surfaces spaced from one another to define a gap filled with the polymer sample, the polymer sample being acoustically coupled to the opposed end surfaces of the buffer rods. Ultrasonic waves are transmitted through one of the buffer rods in a direction toward the polymer sample for interaction therewith, and the polymer sample is subjected to controlled temperature or pressure variations over a predetermined period of time, the variation in temperature or pressure being effected via the buffer rods.